1. Field of the Invention
The present invention relates to a fuel rod auto-loading apparatus for a nuclear fuel assembly and, more particularly, to a fuel rod auto-loading apparatus for disposing fuel rods, each of which is assembled as a unit part, in a fuel rod case in a bundle to assemble the fuel rods into a nuclear fuel assembly.
2. Description of the Related Art
Nuclear reactors are facilities for artificially controlling a fission chain reaction of a fissionable material in order to use thermal energy generated from nuclear fission as power.
Referring to FIG. 15, a nuclear fuel assembly includes spacer grids 2 into which fuel rods are inserted, numerous guide thimbles 3 fixed to the spacer grids 2, an upper end fitting 3 fastened to upper ends of the guide thimbles 2, and a lower end fitting 4 fastened to lower ends of the guide thimbles 2. Each fuel rod is supported by dimples and springs formed on each spacer grid 2.
The fuel rod is made up of a cladding tube, end plugs, pellets, and springs. The fuel rod is manufactured by enriching uranium-235 of 2 to 5% to form a cylindrical nuclear fuel pellet of about 5 g, charging the pellets into the cladding tube, inserting the springs, and sealing the cladding tube using the end plugs.
The fuel rods manufactured in this way is assembled into the nuclear fuel assembly having a bundle of several hundreds of fuel rods. The nuclear fuel assembly is installed in a reactor core, and is burnt.
Thus, numerous fuel rods are required in the reactor core, and it is very important to efficiently manufacture and manage the fuel rods.
Particularly, the nuclear fuel assembly disposed in the reactor core is disposed so as to have a different enrichment level according to a position of the core, and is replaced.
For effective burnup, the fuel rods constituting the nuclear fuel assembly may be disposed so as to have a different type (e.g. a different enrichment level) according to a position at which they are disposed in the nuclear fuel assembly.
The different types of fuel rods need be discriminated and managed in the manufacturing process. The manufactured fuel rods are integratedly managed so as to be able to effectively find and rapidly assemble fuel rods of desired types when the nuclear fuel assembly is manufactured.
For example, the application of the present invention proposes an automated nuclear fuel rod loading bar and equipment for a nuclear fuel assembly in Korean Patent No. 10-0982297 (granted on Sep. 8, 2010) in order to increase a fuel rod loading speed for the nuclear fuel assembly.